How to unstick your zoom!

[shiato storm]

recently my 100-400 has been getting a little sticky - taking a bit of a nudge to get it sliding after its been in its case or with the locking ring keeping at a set length BUT I do believe I've found a simple but effective way of freeing up some movement...
take a piece of paper and it into tear several small strips, now, very carefully slide one up between locking ring and lens barrel and gently run it round the inside until you come back to your start point. I managed to dislodge tons of black crap that came out with the paper. I imagine that there is a layer of those black brushes similar to those on the tripod mount, using a strip of paper will not upset them, perhaps cleaning them a bit does them a favour. anyway the lens is running much smoother now...
just thought that might help anyone.

[ron chappel]

I wonder if that was some kind of 'filter' to keep dust out? I've often wondered what kind of antidust seals lenses use (i know cheap lenses have none at all)

...not that you've damaged anything-if it was coming out when rubbed with paper than it was had it anyway

[shiato storm]

I figured a thin bit of paper wouldn't do much harm either way...and as I said it seems to have done the trick.
and I also suspect its a little more robust than a cheap lens...cause this isn't exactly what you'd call a cheap lens.